$re = '/(#EXTM3U\s+|#EXTINF:\d+,|(.*\.\w{3,4}).*\s+)/';
$str = '#EXTM3U
#EXTINF:419,Alice in Chains - Rotten Apple
http://192.168.101.22:80/movies/9975.mkv
#EXTINF:260,Alice in Chains - Nutshell
http://192.168.101.22:80/movies/1254.mkv
#EXTINF:255,Alice in Chains - I Stay Away
http://192.168.101.22:80/movies/1254.mkv
#EXTINF:256,Alice in Chains - No Excuses
Alice in Chains_Jar of Flies_04_No Excuses.mp3
#EXTINF:157,Alice in Chains - Whale And Wasp
Alice in Chains_Jar of Flies_05_Whale And Wasp.mp3
#EXTINF:263,Alice in Chains - Don\'t Follow
Alice in Chains_Jar of Flies_06_Don\'t Follow.mp3
#EXTINF:245,Alice in Chains - Swing On This
Alice in Chains_Jar of Flies_07_Swing On This.mp3
';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php